Time Duration Calculator

Free Time Duration Calculator - Work Out Hours Between Two Times

Working out how many hours you actually worked sounds simple, until you try to do it in your head. You clocked in at 8:47, clocked out at 5:12, took a 32-minute lunch and a couple of short breaks — now what? This time duration calculator does that math for you in one second. Just type in a start time and an end time, add any breaks you took, and it instantly shows you the total hours worked, both as a clean decimal number and as an easy-to-read hours-and-minutes format.

It's built for real work situations, not just textbook examples. That means it handles overnight shifts that run past midnight, lets you add as many separate breaks as you need, can round your total to match how your workplace tracks time, and can even split your hours into regular time and overtime and estimate your pay. Whether you're filling out a timesheet, checking a paycheck, or just curious how long you actually worked today, this tool gives you an accurate answer without any manual counting.

How to Use This Time Duration Calculator

This calculator is designed to be quick for a simple shift, but it also has extra options for anyone who needs more detail. Here's how it works:

• Enter your Start Time and End Time using the time pickers. Your browser will show them in 12-hour (AM/PM) or 24-hour format depending on your device settings.
• If your end time is earlier in the clock than your start time (for example, 10:00 PM to 6:00 AM), the calculator automatically treats it as an overnight shift and adds the missing day.
• Add any unpaid breaks under "Unpaid Breaks." You can name each one — lunch, coffee break, meeting — and enter how many minutes it lasted. Add as many as you need, or remove the default one if you didn't take a break.
• Open Advanced Options if you want to round the result, calculate daily overtime, or estimate pay from an hourly rate.
• Your net working hours update instantly at the top, in both hours-and-minutes and decimal form, along with a full breakdown further down the page.

How Does This Calculator Work Out Hours Worked?

Behind the scenes, the calculator follows the same logic a payroll clerk would use, just faster and without any risk of a manual mistake. It works through the calculation in a clear order.

• Step 1 — Convert the start time and end time into minutes since midnight, so they can be compared directly.
• Step 2 — Check whether the end time is earlier than the start time. If it is, the calculator assumes the shift runs past midnight and adds 24 hours to the end time before continuing.
• Step 3 — Subtract the start time from the (adjusted) end time to get the gross duration — the full stretch of time from clock-in to clock-out.
• Step 4 — Add up every break you entered and subtract that total from the gross duration to get your net working time, which is the number that actually matters for pay and timesheets.
• Step 5 — If rounding is turned on, the net time is rounded to the nearest interval you chose. If overtime is turned on, anything past your daily threshold is split out separately and, if a pay rate is set, multiplied by your overtime rate.

Decimal Hours vs Hours and Minutes: Why This Calculator Shows Both

There are two common ways to write down how long someone worked, and they look almost identical but mean very different things if you mix them up. "7 hours and 30 minutes" is the hours-and-minutes format most people think in naturally. "7.5 hours" is the decimal format that payroll systems and spreadsheets actually use for calculations, because you can't multiply an hourly rate by 30 minutes directly — you need 0.5 of an hour.

This is where a lot of manual mistakes creep in. Thirty minutes is not ".30" of an hour, it's ".50," because 30 minutes is half of 60 minutes, not 30 hundredths of a day. This calculator handles that conversion automatically and shows you both formats side by side, so you never have to guess whether a spreadsheet formula wants 7:30 or 7.5.

Handling Overnight Shifts Correctly

Night shifts, security work, hospitality, and healthcare jobs regularly involve a start time on one day and an end time the following day, like 11:00 PM to 7:00 AM. A naive calculation would try to subtract 11:00 PM from 7:00 AM and get a negative number, which doesn't make sense for a length of time.

This calculator checks for that automatically. Whenever the end time you enter comes before the start time on the clock, it assumes you mean the next day and adds a full 24 hours before doing the subtraction. You don't need a separate "overnight" toggle or to do any mental math — just enter the two clock times exactly as they appear on your timesheet or schedule.

Adding Multiple Breaks

Very few work shifts have just one clean break. A typical day might include a 30-minute lunch plus two 10-minute breaks, and each one usually needs to be unpaid time subtracted from the total. This calculator lets you add as many separate break entries as you need, each with its own label and length in minutes, so the breakdown stays clear rather than lumping everything into one number.

If the breaks you enter somehow add up to more time than the shift itself — for example, a 4-hour shift with 5 hours of "breaks" entered by mistake — the calculator caps the total break time at the full length of the shift, so your net working time never goes negative.

Rounding Hours the Way Employers Actually Do

Many workplaces don't pay for the exact minute you clocked in and out — they round to a fixed interval instead, most commonly the nearest 5, 6, 10, or 15 minutes. Rounding to the nearest 6 minutes is especially common because 6 minutes is exactly one-tenth of an hour, which makes payroll math cleaner.

This calculator lets you pick a rounding interval so your total matches how your employer actually calculates pay, instead of showing you the raw, unrounded figure that might not line up with your paycheck.

Understanding the Overtime Split

Turning on "Calculate daily overtime" lets you set a daily hours threshold — commonly 8 hours in many places — along with an overtime multiplier, most often 1.5× ("time and a half"). Once your net working time crosses that threshold, everything beyond it is split out as overtime hours instead of regular hours.

This is a general-purpose calculation, not a substitute for your specific employment contract or local labor law, since overtime rules vary by country, state, industry, and sometimes by union agreement. Use it as a quick way to see the split and estimate pay, and check your actual pay stub or company policy for anything that affects your paycheck.

Estimating Pay From an Hourly Rate

If you turn on the pay estimate and enter your hourly rate, the calculator multiplies your regular hours by that rate, and — if overtime is also turned on — multiplies your overtime hours by the rate and the overtime multiplier separately, then adds the two together for an estimated total. This is a fast way to sanity-check a paycheck or figure out roughly what a shift is worth before you've even worked it, especially useful for freelancers, contractors, and hourly employees comparing different shift lengths.

Common Ways People Use a Time Duration Calculator

Calculating elapsed time between two clock readings comes up constantly, in both work and everyday situations.

• Filling in a timesheet at the end of a shift or pay period without doing mental math.
• Double-checking that a paycheck matches the hours actually worked, including any overtime.
• Freelancers and contractors billing clients by the hour and needing an exact, defensible number.
• Estimating pay for a shift before agreeing to work it, especially for part-time or gig work.
• Tracking study sessions, workouts, or focused work blocks by clock time instead of a running stopwatch.
• Working out how long a flight, drive, or event lasted from a departure and arrival time.
• Managers building a weekly schedule and needing to check that shift lengths add up correctly, including overnight coverage.

Common Mistakes People Make Calculating Hours by Hand

A handful of small errors show up again and again when people try to work out elapsed time on paper or in their head, and this calculator avoids all of them automatically.

• Treating minutes like a decimal directly — thinking 45 minutes is ".45" of an hour instead of the correct ".75."
• Forgetting to subtract unpaid break time, which quietly inflates the total.
• Getting a negative or confusing result on an overnight shift because midnight wasn't accounted for.
• Adding up several separate breaks incorrectly, especially when they're written in different formats like "30 min" and "quarter hour."
• Mixing up 12-hour AM/PM times, particularly around noon and midnight, which are easy to enter backwards.
• Applying an overtime rate to the whole shift instead of just the hours past the threshold.